1. Field of the Invention
The present invention regards a method for controlling the deposition of elementary semifinished products in a process for building tyres for vehicle wheels. The invention also refers to an apparatus for controlling the deposition of elementary semifinished products in a process for building tyres for vehicle wheels.
2. Description of the Related Art
A tyre for vehicle wheels generally comprises a carcass structure comprising at least one carcass ply having respectively opposite end flaps respectively engaged to annular anchoring structures, integrated in the areas usually referred to as “beads”, defining the radially internal circumferential edges of the tyre.
A belt structure comprising one or more belt layers, positioned radially superimposed on each other and relative to the carcass ply, having textile or metallic reinforcement cords cross-oriented and/or substantially parallel to the circumferential direction of extension of the tyre is associated to the carcass structure. A tread band, also made of elastomeric material, just like the other semifinished products constituting the tyre, is applied in radially external position.
In addition, respective sidewalls of elastomeric material are applied in axially external position onto the side surfaces of the carcass structure, each extending from one of the side edges of the tread band until close to the respective annular anchoring structure to the beads. In tyres of the “tubeless” type, an airtight cover layer, usually referred to as “liner”, covers the inner surfaces of the tyre.
The invention particularly applies to processes in which the tyres are built by associating elementary semifinished products to each other, depositing the same on suitable forming supports.
Depending on the type of process used, the forming support may be a substantially toroidal-shaped or substantially cylindrical-shaped building drum.
The expression “elementary semifinished product” is used to indicate a continuous elongated element, preferably having a flat transverse section, made of elastomeric material. Preferably said “elementary semifinished product” is a piece of said elongated element cut to size. Even more preferably said “elementary semifinished product” embeds one or more reinforcement textile or metallic cords arranged parallel relative to each other in the longitudinal direction of the same elongated element.
Such elementary semifinished products, when comprising the aforementioned reinforcement cords, if they have a major longitudinal dimension are referred to as “strip-like elements” hereinafter. The strip-like elements, suitably approached or partly superimposed on each other, cooperate to form various components of a tyre. In particular, the strip-like elements may be used for the manufacturing one or more carcass plies of the carcass structure and/or one or more belt strips or layers of the belt structure of the tyre.
In some cases, the semifinished elements may also have a longitudinal dimension and a transverse dimension comparable to each other, preferably substantially equal to each other. In such case they are plate-like elements, having a substantially quadrangular shape in plain view. Elementary semifinished products of this type may be used, in tyre building, and they are hereinafter referred to as “reinforcement elements”.
The expression “elementary semifinished product” is also used to indicate a component of the tyre made of elastomeric material not reinforced by cords.
The expression “tyre being processed” is used to indicate a forming support of the tyre with at least one component portion of the tyre deposited on the support itself.
The expression “component” of the tyre is used to indicate any component adapted to serve a function in the tyre or a portion thereof, selected for example from among: liner, under-liner, carcass ply/plies, under-belt insert, belt strips both crossed with respect to each other and of the zero degree type, bonding sheet for the tread band, tread band, sidewalls, bead core, bead filling, textile, metallic reinforcement inserts or inserts made of elastomeric material alone, anti-abrasive inserts, sidewall inserts.
The expression “detecting an image” is used to indicate a matrix of spots or frames, in analogue or digital format, provided as output by a detecting device, and defined by the incident radiation on a detecting window of such device in a given time interval, referred to as “exposure time” or “shutter speed”. During this time interval the device is maintained uninterruptedly active, in such a manner that all detectable radiations which, in the time interval, have an impact on the detecting window, are represented in a single image, i.e. the detected image. The radiation (or radiations) which cooperate/s to form the image are those to which the detecting device is sensitive, and they are comprised, for example, in a given interval of wavelengths.